Stereotaxic injection into the brain is facilitated by secure cranial immobilization in a stereotaxic frame. This has made it possible to accurately place transplants in the brain. However, stereotaxic injection into the spinal cord is more difficult due to the small size of the spinal cord, its constant motion in several planes relative to the vertebral spine, and its exquisite vulnerability to injury. For these reasons current spinal cord injection techniques rely upon direct visualization of the spinal cord during an open surgical procedure and immobilization of the spine in clamps during cellular injections. Since this type of surgical exposure is usually necessary to create an experimental spinal cord injury, various types of transplant techniques are possible using the same exposure.
Many spinal injuries require decompression and vertebral column stabilization surgery soon after hospitalization. This surgical opportunity may not be an optimal time for cellular injection to facilitate repair. Once this initial surgery has occurred, it is undesirable to disturb the progress of wound healing and bone fusion. Therefore, it is important to develop strategies of cell transplantation into the spinal cord compatible with minimal disturbance of the wound healing process. Cellular transplantation into the injured spinal cord has been used to study injury and repair responses in experimental models. Some clinical trials of cellular transplantation (e.g. activated macrophages, ensheathing glia) into the injured human spinal cord have been initiated using conventional open surgical techniques. Cell suspensions can be transplanted to create trails or columns of cells to partially reconstruct axonal pathways. In the spinal cord this requires either several closely spaced separate injections or a technique to enter the cord at a shallow angle. Currently, almost all injections into the spinal cord result in a tract defined by the needle path which is generally perpendicular to the longitudinal axis of the spinal cord.
There exists a need for a minimally invasive technique and system for cellular delivery in the spinal cord. Accordingly, the present invention provides a minimal access endoscope-assisted technique via a lumbar puncture approach without the need to create a large surgical incision. Cellular transplantation is performed under endoscopic visualization based on percutaneous access, remote from the injury site. Delivery of cells or cell suspension provides a trail of cells in the spinal cord which may span from the site of axonal injury to a useful target neuronal population. Regeneration of the damaged axons to the target neuron occurs via the transplanted supportive cells. The trail of cells is defined by the needle path which is generally parallel to the longitudinal axis of the spinal cord.